I'm working on a simple top-down game and I'm trying to perfect movement and collision detection.

While I was going through someone's game code, I noticed that they created an entire class dedicated to input handling. In the class they handle toggling any booleans for keypress and keyrelease. There is other functionality, but I'm still trying to figure it all out.

The question is if it is worth the effort to create this class, or if I should just use the keylistener in my GamePanel class? I can create some booleans to help out with movement and collision here.

There's nothing* saying you HAVE to use any more than a single class in java. But following good practices (especially Object-Oriented design practices), an InputHandler class makes sense, and in my own projects in C# I find it useful to have that functionality extracted into its own class with easier-to-use and easier-to-read method calls.

For example, my InputHandler class (mimicing other project designs) tracks the state of all input devices each frame and stores those, so that at any point I can check boolean combinations of the current and 1-frame-previous device states to be able to catch if a key was just pressed, if it's being held, if it's just been released, what the mousewheel is doing, and on and on. The boolean checks are a little lengthy, so it's nice to just write a "isKeyJustPressed(KeyMap[Actions.Jump])" check instead.

*not a java expert, some contradiction to this hastily made claim may exist

I'm not a Java person either so I can't speak from any position of authority as regards what may or may not be considered good Java practices, but - a good general rule I've found useful before is this. "If you have one of something, there exists a possibility that sometime you may need more than one". Not-so far-fetched input examples might be a 4-player split-screen mode, or a two-player co-op mode on a single screen.

That aside, I'd be inclined to have a separate class anyway. It gives cleaner separation between input and other game logic/events. And if it ever should happen that you do need more than one, it'll go much easier on you.

It appears that the gentleman thought C++ was extremely difficult and he was overjoyed that the machine was absorbing it; he understood that good C++ is difficult but the best C++ is well-nigh unintelligible.

Have a good read, trust me its worth it. Its not a GOLDEN RULE, but as mentioned in the bottom article, it does help very much in the early stages because you aren't ripping a single class to pieces to try and get something working.

And yes, you should. As others have mentioned, re-usability is a must for game development. You could create a ScoreTracker class that tracks your players score. Then you could re-use that class for all your future projects, you can add to it, improve it or make it completely bespoke.

And yes, you should. As others have mentioned, re-usability is a must for game development. You could create a ScoreTracker class that tracks your players score. Then you could re-use that class for all your future projects, you can add to it, improve it or make it completely bespoke.

Exactly

I even have my own timer class that I use for calculating fps, time since last frame, amongst other things...

My reasoning? Timers can be a right proper turd in getting right. Once you get it right, you will want to keep it.